Group Housing of Dry Sows – a Report from the IGN


There is a growing concern about the impact of the welfare of sows when kept for extended periods either tethered or in gestation stalls. Several European countries have banned the use of gestation stalls and tethers in favour of group housing. Many reports have focused on the increased animal welfare for sows when they are kept in group housing systems.But does group housing automatically translate into increased welfare for the sow?

A recent report released by the International Society of Livestock Husbandry looked at the question of the welfare of sows in sixteen different loose-housing systems. Thirteen experts on pig housing, with experience with several group housing systems from Austria, Denmark, Germany, Switzerland, the Netherlands and the United Kingdom, met to discuss the pros and cons of the 16 existing production systems. This approach was taken because the costs of setting up a similar research project would be too great. The International Society of Livestock Husbandry (IGN) was founded in 1978 with the aim to promote those methods of treatment and husbandry of farm animals that are adequate to their biological needs. IGN works as a mediator between science and practice and uses various means to deal with the diverse aspects of livestock husbandry. The sixteen housing systems were very diverse. Systems were divided into small group systems (4 to 20 sows) with manual or mechanical feeding and large groups (40 – 100 sows) equipped with electronic feeding stations (EFS). Small and large group systems included a mixture of indoor and outdoor facilities; some systems provided roughage, some not. The systems included three types of social groupings: stable groups (established social rank order), rotating groups (change to another housing system according to the productive cycle) and dynamic groups (parts of the whole group are changed more or less regularly.) The experts were supplied with detailed information of each system prior to a three day face to face meeting in September of 1998. Each system was well investigated or observed over several years by at least one of the participants. During the three days, presentations were given on each system using floor plans and giving detailed information about management. Participants developed an assessment tool based on seven behavioral domains (e.g. social behavior, feed intake behavior, etc.) and using scores from 1 “not sufficient or bad” to 5 “very good or excellent.” Evaluations were based on the assumption that each farm maintained comparable and adequate management, hygiene, nutrition and care in all housing systems. The outdoor housing system was ranked the best system by the team of 13 experts. This is not surprising since number six consisted of a group size of 8 sows in stable groups with an activity area of 500 m� (about 8 sows per acre), resting kennels with straw litter, mud wallow, trees for shade, electric fencing with double wire and no additional roughage. However, the experts point out that this system was very rare and very unique – and that the wide variety of housing choice and low stocking density provided a low management risk. There were 6 housing systems that were ranked second – 3 small groups and 3 large. The experts used this result to conclude that good welfare is possible both in large and small group systems. The second-ranked small systems each included a separate lying and elimination area, a resting area with straw bedding and a division of the feeding trough into separate places.

The larger systems all included EFS’s: the second- place large systems provided either roughage ad lib. in racks or fresh straw and pelleted concentrate to reduce competition. Overall, the experts of the IGN workshop concluded that a change from individual housing systems (tethers, stalls) does not automatically lead to a uniform level of animal welfare. There are systems that improve the welfare of the sows – these systems need to be promoted. However, each housing system has to be assessed separately, with consideration given to the behavioral needs of the dry sow. Labour conditions, technical, structural, environmental as well as economic advantages and disadvantages of each housing system need to considered, as well, when looking at loose housing.


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